The ever more stringent performance requirements of the electronic packaging industry mandate the development of polymers with lower dielectric constant and lower moisture absorption. Improvement in these properties has in the past been effected by the introduction of fluorine into the polymer. Unfortunately, this was always accompanied by deterioration of other properties, such as lowering of the glass transition temperature, increasing the coefficient of thermal expansion, and increasing solvent sensitivity. Accordingly, the present invention relates to a new class of stiff, fluorinated monomers, based on two novel pentacyclic core systems, 12H,14H-5,7-dioxapentacene containing perfluoroalkyl, or perfluoroalkyl and aryl substituents in the 12,14 positions, and on 5H,12H,7-14-dioxapentacene containing perfluoroalkyl, or perfluoroalkyl and aryl substituents in the 5,12 positions.
These monomers have utility in the preparation of advanced high-performance polymers, particularly polyimides. The rigid pentacyclic core decreases the coefficient of thermal expansion of the polymers, while the fluorinated substituents improve the dielectric constant, and water absorption properties.